Various polyester resins are used in a wide range of fields since they can be molded into films, sheets, deformed materials, fibers, tubes, containers and the like by various molding processes and the like. Polyesters that are most frequently used are aromatic polyesters that are obtained by using an aromatic dicarboxylic acid such as terephthalic acid or isophthalic acid as a raw material, and these are excellent in heat-resistance, toughness and the like since these contain aromatic groups.
In recent years, shifting of semiconductor laser light sources to lower wavelength areas has progressed, and blue laser, UV light laser and the like have come into use as light sources for light signals. In accordance to this, demand for increase in transparency in polymer materials that are used for optical materials, electronic parts and the like has been increased. However, it was difficult to apply the above-mentioned aromatic polyesters to such fields since they are poor in ultraviolet resistance, light transmittance and the like.
Therefore, some polyesters having an alicyclic structure have been gradually used in fields for that needs the above-mentioned transparency since they are excellent in heat-resistance, transparency and water resistance. As processes for the production of alicyclic polyesters, many processes using a saturated cyclic aliphatic primary diol such as 1,4-cyclohexane dimethanol have been suggested (Patent Document 1). Since an alkylene group is inserted between a hydroxy group and a saturated cyclic aliphatic group in a saturated cyclic aliphatic primary diol, the obtained alicyclic polyester resin had aliphatic properties, and those having a cyclohexane ring backbone had low heat-resistance. Therefore, sufficient properties for the above-mentioned applications could not be obtained.
Furthermore, alicyclic polyesters composed of a dicarboxylic acid component including 4,4′-bicyclohexyldicarboxylic acid as a main component and an alicyclic diol has been suggested for improving the heat-resistance of the alicyclic polyesters (Patent Document 2). However, the heat-resistance of these was still not sufficient.
Since before, a raw material for alicyclic polyesters having excellent heat-resistance and the like has been sought.